
//
public class MyLinkedList {

    class ListNode {
        public int val;
        public ListNode next;

        public ListNode(int val) {
            this.val = val;
        }
    }

    public ListNode head;

    //头插法
    public void addFirst(int data) {
        ListNode node = new ListNode(data);
        if (head == null) {
            head = node;
            return;
        }
        node.next = head;
        head = node;
    }

    //尾插法
    public void addLast(int data) {
        ListNode node = new ListNode(data);
        if (head == null) {
            head = node;
            return;
        }
        ListNode cur = head;
        while (cur.next != null) {
            cur = cur.next;
        }
        cur.next = node;
    }

    //任意位置插入,第一个数据节点为0号下标
    public boolean addIndex(int index,int data) {
        return false;
    }

    //查找是否包含关键字key是否在单链表当中
    public boolean contains(int key) {
        return false;

    }

    //删除第一次出现关键字为key的节点
    public void remove(int key) {

    }

    //删除所有值为key的节点
    public void removeAllKey(int key) {

    }

    //得到单链表的长度
    public int size() {
        int count = 0;
        ListNode cur = head;
        while (cur != null) {
            cur = cur.next;
            count++;
        }
        return count;
    }

    public void display() {
        ListNode cur = head;
        while (cur != null) {
            System.out.print(cur.val + " ");
            cur = cur.next;
        }
        System.out.println();
    }

    public void clear() {
        head = null;
    }
}
